Alternators

[FLtoAK]

Thanks again Davydd. I skimmed through the white paper and it will be very useful. Thanks for sending the link. Wonder what size wire they use to connect the Volta alternator in the 13.5kv system to the batteries. A search on Advanced RV Volta brings up many interesting results. Looking forward to all the homework! The May event looks worth attending. Hopefully, we can make it next year.

[markopolo]

Originally Posted by GallenH

......................... I can't figure out the size of my current alternator. I do know that there is a 40A circuit breaker between the alternator and the battery. ..........

Looks like it would have been either a 117A or 136A alternator for the 1997 model year Dodge Maxivan.

That's similar to my GM van of the same year.

You can look-up or decode the RPO codes on GM vans. Those codes list all the as built options including the alternator. I don't know if there is that option with your Dodge van. A dealer should be able to tell you.

I would not be at all suprised to see 8AWG wire used on the battery runs in a '97 van. A 40A breaker is often used with 8AWG. 8AWG + diode type isolator (if used) would result in less amps into the house battery because of the drop in the voltage actually reaching that battery. You could drive all day and most likely never overcharge a battery.

[GallenH]

I just got yesterday from Amazon a service manual (used of course) for a 1996 Dodge RAM Van/Wagon (the chassis my 97 was built on). It lists options as an 81A, 117A and 136A alternator. The 136 was a Denso 53008651 which explains my "mystery" number of 5300(small type)8651(large type). You you are correct, markopolo.

Booster: It is a single 40A breaker between the alternator and the battery.

Before I ask any questions again, I'll reread this thread and all of your previous responses and make sure that you haven't already answered them.

thx.glenn

[Davydd]

Originally Posted by FLtoAK

Thanks again Davydd. I skimmed through the white paper and it will be very useful. Thanks for sending the link. Wonder what size wire they use to connect the Volta alternator in the 13.5kv system to the batteries. A search on Advanced RV Volta brings up many interesting results. Looking forward to all the homework! The May event looks worth attending. Hopefully, we can make it next year.

I think Volta is a turnkey system where you have to buy only what they engineer and provide. I don't even know if they sell to DIYfers. I haven't been to their site lately. But anyway since it is a 56v system the wires will be much lighter than a 12V system. For instance my wire from the alternator to the batteries is 4.0 which is almost a 1/2" diameter copper wire to handle the amps. That's massive and over 20 ft. long.

[FLtoAK]

Originally Posted by Davydd

I think Volta is a turnkey system where you have to buy only what they engineer and provide. I don't even know if they sell to DIYfers. I haven't been to their site lately. But anyway since it is a 56v system the wires will be much lighter than a 12V system. For instance my wire from the alternator to the batteries is 4.0 which is almost a 1/2" diameter copper wire to handle the amps. That's massive and over 20 ft. long.

Yes, I did realize that the wire size would be better with a 56v output alternator when I found that out, which makes this system that much more attractive.

[themexicandoctor]

Good question Gallen as I have been watching.

PS. The range with the DC Fridge does need to be wider as I am discovering during Day Two of this 7 Day Heatwave Los Angeles heatwave

[GallenH]

So my current fridge is 3cf. In looking at similar sized compressor fridges they claim that the draw is 2.2A. If that fridge was constantly running all 24hrs it appears to me that it would take c.53A. From that I'm assuming that in HOT (caps for SW temps) climates during the HOT (don't want to underemphasize our wonderful weather in PHX) part of the year, the fridge may indeed run continuously and therefore draw 53AH from your battery complement. Is that correct?

[themexicandoctor]

If you can find that earlier thread of mine about BEST COMPRESSOR FRIDGE you will discover that amps stated are not necessarily a reliable indicator.

But in this heatwave, without driving, my fridge has been using about 34-40amps per day.

The exact amount still has to be decided.

At the same time, the higher quality DC fridges ie; Novakool, Isotherm, Vitrifrigo should have a 50% on 50% off cycle in perfect conditions but with a heat wave, poor venting (I have adequate venting) & other factors drive amp draw.

[themexicandoctor]

Here it is;

https://www.classbforum.com/forums/f...ile-10598.html

[booster]

Of note, the posters, when talking about frig power use, are talking about amp hours per day, not amps or the running amps of the frig that you see in the specs for them.


The running amps given in the specs are really a pretty poor way of determining how much energy a frig will use in real life. In fact it is also not even really a great way to know what the worst case power use would be as how many amps that the frig uses at any given point in time will change with the conditions it is running in.


I have noticed that a lot of the frig manufacturers are touting lower running amps now they did 5+ years ago. Back then it was typical to see running amps given of 3.2-3.5 amps in the units. Now we see most of the them in the mid to low 2 amps range. It is easy to do by just changing the compressor speed, which is adjustable.



In reality, this change to lower speed can make the frig less efficient in the real world as it may not be running at the most efficient point in the compressor curve. I have posted the efficiency charts several times on the forum to show how it works. Even though the running amps are lower, the runtime increases enough to make them use more energy total per day of running. I think the low published amps are a mere marketing thing, as it makes no sense otherwise. They never seem to give the spec running conditions either. Lower running amp setting also will make the frig recover a bit more slowly when warm food or drinks are put in as it is running at lower cooling capacity.


Bottom line is that the way the manufacturers are choosing to spec their units makes it nearly impossible to accurately compare them or know how much power they will actually use in your camping.

[GeorgeRa]

Originally Posted by Davydd

.................

BTW, this is what 420 watts of solar looks like in 3 panel on an extended van Sprinter of 24 foot. If I had less, my comparison numbers would be worse. That's why I am going no solar on my next van.

What is on the front panel rear left corner, a vent? I have never seen anyone blocking solar panels. If this panel has all cells wired in series not much energy can be harvested from it. I would assume all 3 panels are wired in parallel, if in series the output can be dramatically diminished by the front panel.

[GallenH]

Originally Posted by booster

Of note, the posters, when talking about frig power use, are talking about amp hours per day, not amps or the running amps of the frig that you see in the specs for them.


The running amps given in the specs are really a pretty poor way of determining how much energy a frig will use in real life. In fact it is also not even really a great way to know what the worst case power use would be as how many amps that the frig uses at any given point in time will change with the conditions it is running in.


I have noticed that a lot of the frig manufacturers are touting lower running amps now they did 5+ years ago. Back then it was typical to see running amps given of 3.2-3.5 amps in the units. Now we see most of the them in the mid to low 2 amps range. It is easy to do by just changing the compressor speed, which is adjustable.



In reality, this change to lower speed can make the frig less efficient in the real world as it may not be running at the most efficient point in the compressor curve. I have posted the efficiency charts several times on the forum to show how it works. Even though the running amps are lower, the runtime increases enough to make them use more energy total per day of running. I think the low published amps are a mere marketing thing, as it makes no sense otherwise. They never seem to give the spec running conditions either. Lower running amp setting also will make the frig recover a bit more slowly when warm food or drinks are put in as it is running at lower cooling capacity.


Bottom line is that the way the manufacturers are choosing to spec their units makes it nearly impossible to accurately compare them or know how much power they will actually use in your camping.

This is all good to know. Is my basic assumption that if I turn on my ceiling fan and my monitor shows a draw of, say, 1a, that if I left it on for an hour it would consume 1AH of my battery?

If I turn it on high it will have a bigger, say 1.5a draw. But in terms of cooling down the RV, it would take less time and maybe use less AH that getting the same effect running the fan on low for longer. That makes sense.

I'll dig the forum for your past posts on efficiency. The challenging thing though is that it would appear that unless companies use the same test setup, you're just shooting in the dark with their specs on consumption.

[Davydd]

Originally Posted by GeorgeRa

What is on the front panel rear left corner, a vent? I have never seen anyone blocking solar panels. If this panel has all cells wired in series not much energy can be harvested from it. I would assume all 3 panels are wired in parallel, if in series the output can be dramatically diminished by the front panel.

Those are flex solar panels adhered to a plastic board a little over 1/8” thick and trimmed in aluminum channels attached to the roof rails to follows the curvature of the roof and of course spans the roof ribs. That is a vent protruding through the white plastic board not the solar panel. The panels themselves are in two series each per panel so if half is in shade the other half will still be fully effective. Each panel in turn has its own MPPT controller, three in all. That white box in front of the air conditioner and behind the Maxxfan is the collection box for the wires coming off the solar panels.

[GallenH]

Originally Posted by Davydd

Those are flex solar panels adhered to a plastic board a little over 1/8” thick and trimmed in aluminum channels attached to the roof rails to follows the curvature of the roof and of course spans the roof ribs. That is a vent protruding through the white plastic board not the solar panel. The panels themselves are in two series each per panel so if half is in shade the other half will still be fully effective. Each panel in turn has its own MPPT controller, three in all. That white box in front of the air conditioner and behind the Maxxfan is the collection box for the wires coming off the solar panels.

Very interesting. Do you know the mfg of the flex panels?

[Davydd]

Originally Posted by GallenH

Very interesting. Do you know the mfg of the flex panels?

No, I don't. ARV could tell you. They are flex panels that I have seen in their shop rolled up and being cut with a mat knife. Their zoned panels and mounting them on a plastic board and trimmed in aluminum channels are their design not the flex panel manufacturer and they as far as I can tell aren't doing that design in any longer. So I would think any flex panel would do. After 4.5+ years they are not cupped like I've read in some flex topics.

As I have mentioned several times, I am not planning on any solar at all in my next van so have decluttered my mind of any research. I've noticed several customers have foregone solar panels at ARV with high capacity lithium ion batteries and second alternators. I came to that conclusion very early on.

[booster]

Originally Posted by GallenH

This is all good to know. Is my basic assumption that if I turn on my ceiling fan and my monitor shows a draw of, say, 1a, that if I left it on for an hour it would consume 1AH of my battery?

If I turn it on high it will have a bigger, say 1.5a draw. But in terms of cooling down the RV, it would take less time and maybe use less AH that getting the same effect running the fan on low for longer. That makes sense.

I'll dig the forum for your past posts on efficiency. The challenging thing though is that it would appear that unless companies use the same test setup, you're just shooting in the dark with their specs on consumption.

Yes amps and amp hours will be the same for a constant amp draw for one hour.


You are exactly right on the manufacturer's specs for energy use of the frigs. For the most part you are shooting in the dark, and there is really no good reason for it except sales deception, I think, to intentionally select a spec that means little to publish, eg running amps.


If you go the Isotherm website, you will find that they list 24 hour power use numbers under controlled conditions that are called out in a standard industry test spec. The also list those conditions so you can see how the match what you do in real life.

[GeorgeRa]

Originally Posted by Davydd

Those are flex solar panels adhered to a plastic board a little over 1/8” thick and trimmed in aluminum channels attached to the roof rails to follows the curvature of the roof and of course spans the roof ribs. That is a vent protruding through the white plastic board not the solar panel. The panels themselves are in two series each per panel so if half is in shade the other half will still be fully effective. Each panel in turn has its own MPPT controller, three in all. That white box in front of the air conditioner and behind the Maxxfan is the collection box for the wires coming off the solar panels.

Thank you for explanation. I am puzzled with 2 strings in series per panel. Typical 12V nominal panels are minimum 36 cells. Based on your picture it seems as your panels are 50 cells each and for 2 strings minimum 72 cells would be required. ARL must be using ByPassDiode for each cell to have working panel with this cutout for a vent.